Author Topic: FAQs  (Read 2723 times)

Offline Flugzeugwerke

  • Moderator
  • Hero Member
  • *****
  • Posts: 4230
FAQs
« on: April 22, 2015, 09:37:14 AM »
1) What is this stuff anyway?

The parts we are currently offering via Shapeways are made of an acrylic photopolymer. It is squirted in molten form onto a bed, layer by layer (along with a gel-like support material) and cured with UV light. The finished material is similar to other acrylic plastics. It is more brittle and somewhat harder than styrene, but it can be drilled, sanded, filed, carved and sawn and with the same sorts of tools we use with our plastic models. It will arrive with most, but not all, of the waxy gel removed. In order for paint and glue to adhere it is highly recommended that you clean the parts first. More on that below...

Offline Flugzeugwerke

  • Moderator
  • Hero Member
  • *****
  • Posts: 4230
Re: FAQs
« Reply #1 on: April 22, 2015, 09:59:34 AM »
2) ok, how do I clean the gunk off? (And why doesn't it come with this stuff cleaned off already?)

There are various methods touted for removing the remaining residue on the parts, of which we can recommend two:

-- scrubbing the part carefully with a soft toothbrush in dishwashing liquid and lukewarm water. No icky chemicals, but there is the risk of breaking fragile parts, so caution is advised.

-- simply soaking the parts for not more than 10 to 15 minutes in acetone ( or acetone-based nail polish remover.) Care must be taken not to leave the parts in too long else they will begin to go soft.

In either case, when the parts are thoroughly cleaned the areas that had the waxy gel support matrix during printing will turn white and will appear slightly "furry." (See "prepping parts for painting", below.)

Why do they leave the gunk on? It's a bit of a mystery, as it seems to be universally unpopular with the Shapeways designer community. The answer probably lies in the fact that the parts look somewhat irregular after they are thoroughly cleaned. There is considerable lobbying afoot to try and change this policy in favor of having the parts completely cleaned of all residue before shipping (at least as an option) but for now this is the way it is.

Offline Flugzeugwerke

  • Moderator
  • Hero Member
  • *****
  • Posts: 4230
Re: FAQs
« Reply #2 on: April 22, 2015, 11:19:10 AM »
i've cleaned the parts. What should I do to them before painting?

3) At this stage any type of hobby paint should stick satisfactorily. But there are three types of artifacts inherent with the process that may make you want to first apply a filling primer (e.g. Mr. Surfacer) followed by a light sanding:

-- support structure artifacts -- these are the areas that turn white after cleaning, and will present a sightly bumpy texture.

-- print line "jaggies" -- most evident in the "Z" direction of the part, the digital nature of the printing process can cause a staircase effect, especially on very shallow angled surfaces.

 -- tessellation facets: manifested as edges on what otherwise would be smoothly curved surfaces, as these surfaces are ultimately rendered as a finite series of planes (a cylinder is rendered as a solid with x number of sides, etc.)